Power management integrated circuits (PMICs) are employed for managing the power requirements of devices. For example, PMICs are employed to perform power conversion and power control functions. Some PMIC chips incorporate discrete magnetic devices for high frequency power conversion applications. The magnetic devices often occupy about 2 to 3 times the area of a PMIC itself. In order to reduce the whole package size, integrated thin-film magnetics are developed using standard CMOS manufacturing processes.
However, the present processes for fabricating integrated thin-film magnetics yield devices with geometric constraints and limited cross section aspect ratio. For instance, the metal thickness and magnetic core thickness are limited to a few um (e.g., 2 to 5 um). The limited thickness usually results in large DC resistance (e.g., more than 1Ω), and low quality factor (e.g., less than 10).
From the foregoing discussion, it is desirable to provide a process for forming integrated magnetic devices which solves the above-mentioned problems.